Question About the "Forge Enviroments"

So 343 said there would be 3 Forge enviroments in Halo 4… I was a little confused on what they meant by that until I watched GreenSkull’s new video about Forge yesterday, and instead of saying 3 Forge enviroments he said 3 Forge Worlds? So by Forge enviroments did 343 mean Forge Worlds because that would be awesome if there were 3 Forge World maps outside of the 10 multiplayer maps?

There will be 10 MM maps, and 3 different maps specifically made for forge. Sounds pretty awesome to me!